Biology subjects

Oliveira, J. T.

Publications and source records attributed to Oliveira, J. T..

3 recordsLinked to original sources

bioRxiv2021

Oligomeric α-Synuclein induces skin degeneration in a reconstructed human epidermis model

Cell senescence may promote epidermal inflammation and degeneration, termed as inflammaging, which is accompanied by keratinocyte loss, resulting in fine lines of wrinkles. Recent findings showed that healthy elderly skin expresses age- and neuron-related amyloidogenic proteins, such as tau, {beta}-Amyloid34, and -synuclein (-Syn), typically found in patients with neurodegenerative diseases. These proteins form toxic aggregates that trigger inflammatory signals. Herein, we investigated the impact of oligomeric -Syn (O-Syn) on the neurosphere (NP) and the reconstructed human epidermis (RHE) 3D models. First, we found the expression of -Syn, {beta}-Amyloid, and amyloid precursor protein (APP) in the RHE. Second, we challenged the RHE and NP with O-Syn, which decreased RHE regeneration, measured by the percentage of cell proliferation and thickness of the stratum basale, but did not affect NP neurite outgrowth. O-Syn did not decrease the number of human neonatal epidermal keratinocytes (HEKn) but, as seen for the RHE, it also decreased the proliferation of HEKn. We confirmed that the oligomeric, and not the monomeric -Syn species, accounted for the proliferation-decreasing effect. O-Syn also increased the NF-kB nuclear translocation in HEKn analyzed by nucleus/cytoplasm NF-{kappa}B fluorescence intensity. In addition, O-Syn triggered inflammation in the RHE, by increasing the mRNA levels of IL-1{beta} and tumor necrosis factor-alpha (TNF-), and the release of TNF- in a time-dependent manner. These findings show that O-Syn does not affect neurite outgrowth but induces a decrease in keratinocyte proliferation along with epidermal inflammation. With our tridimensional models, we demonstrated that the neurodegenerative protein O-Syn also degenerates the epidermis, drawing attention to the need of target-based screening to prevent and treat the effects of skin aging.

neuroscience↗

bioRxiv2021

Quantitative profiling of axonal guidance proteins during the differentiation of human neurospheres

Axon guidance is required for the establishment of brain circuits. Whether much of the molecular basis of axon guidance is known from animal models, the molecular machinery coordinating axon growth and pathfinding in humans remains to be elucidated. The use of induced pluripotent stem cells (iPSC) from human donors has revolutionized in vitro studies of the human brain. iPSC can be differentiated into neuronal stem cells which can be used to generate neural tissue-like cultures, known as neurospheres, that reproduce, in many aspects, the cell types and molecules present in the brain. Here, we analyzed quantitative changes in the proteome of neurospheres during differentiation. Relative quantification was performed at early time points during differentiation using iTRAQ-based labeling and LC-MS/MS analysis. We identified 6,438 proteins, from which 433 were downregulated and 479 were upregulated during differentiation. We show that human neurospheres have a molecular profile that correlates to the fetal brain. During differentiation, upregulated pathways are related to neuronal development and differentiation, cell adhesion, and axonal guidance whereas cell proliferation pathways were downregulated. We developed a functional assay to check for neurite outgrowth in neurospheres and confirmed that neurite outgrowth potential is increased after 10 days of differentiation and is enhanced by increasing cyclic AMP levels. The proteins identified here represent a resource to monitor neurosphere differentiation and coupled to the neurite outgrowth assay can be used to functionally explore neurological disorders using human neurospheres as a model.

neuroscience↗

bioRxiv2021

A cannabinoid receptor agonist shows anti-inflammatory and survival properties in human SARS-CoV-2-infected iPSC-derived cardiomyocytes

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which can infect several organs, especially impacting respiratory capacity. Among the extrapulmonary manifestations of COVID-19 is myocardial injury, which is associated with a high risk of mortality. Myocardial injury, caused directly or indirectly by SARS-CoV-2 infection, can be triggered by inflammatory processes that cause damage to the heart tissue. Since one of the hallmarks of severe COVID-19 is the "cytokine storm", strategies to control inflammation caused by SARS-CoV-2 infection have been considered. Cannabinoids are known to have anti-inflammatory properties by negatively modulating the release of pro-inflammatory cytokines. Herein, we investigated the effects of the cannabinoid agonist WIN 55,212-2 (WIN) in human iPSC-derived cardiomyocytes (hiPSC-CMs) infected with SARS-CoV-2. WIN did not modify angiotensin-converting enzyme II protein levels, nor reduced viral infection and replication in hiPSC-CMs. On the other hand, WIN reduced the levels of interleukins 6, 8, 18 and tumor necrosis factor-alpha (TNF-) released by infected cells, and attenuated cytotoxic damage measured by the release of lactate dehydrogenase (LDH). Our findings suggest that cannabinoids should be further explored as a complementary therapeutic tool for reducing inflammation in COVID-19 patients.

cell biology↗